Kiss My Lamprey

[Lee Borgersen]

                                     Field Reports:

   More sea lampreys found in lower Knife River


  .....
Sea lampreys are ascending lower reaches of the Knife River on Minnesota's North Shore, a phenomenon that has been occurring only in the past few years, say fisheries biologists with the Minnesota Department of Natural Resources.

DNR officials have caught about 10 lamprey this spring, using nets to scoop them out of the water below the Knife River fish trap. The trap is 0.2 miles upstream from the mouth of the river.

"We first saw them a few years ago," said Cory Goldsworthy, DNR Lake Superior Area fisheries supervisor at French River. "Nick (Peterson, a DNR fisheries specialist) got video of a seagull eating a lamprey."

The presence of sea lampreys in the Knife River has been detected only in years since the 2012 flood, Goldsworthy said. So far, no lampreys have been found upstream from the Knife River fish trap, which DNR biologists use to monitor the upstream and downstream passage of Lake Superior's migratory rainbow trout (steelhead).

Only part of the Knife River flows through the fish trap, located at a set of waterfalls on the river. Goldsworthy said he wasn't sure whether sea lampreys could ascend the falls away from the fish trap.

Sea lampreys ascend other tributaries of Lake Superior to spawn, including the St. Louis River. Those rivers are treated with a lampricide by the U.S. Fish and Wildlife Service to kill larval lampreys.

"Some folks want us to open the (Knife River) fish trap and let the fish go up and down (without being measured and tagged)," Goldsworthy said. "One of the things we've been saying is that if sea lamprey can access the Knife River, there's plenty of access to good spawning habitat."

If enough lamprey were spawning in the river, it would eventually have to be treated with lampricide, he said.

Lampreys, native to the Atlantic Ocean, were able to migrate to the Great Lakes when the Welland Canal was completed in 1929. In Lake Superior, lampreys and overfishing decimated the lake trout population in the 1950s. Only through ongoing control efforts has Lake Superior's lamprey population been held low enough to allow lake trout and other salmonid species to recover.





Cory Goldsworthy, Lake Superior Area fisheries supervisor for the Minnesota Department of Natural Resources, holds an adult lamprey that DNR fisheries biologists netted below the Knife River fish trap this spring. Lampreys use their "suction-cup" mouth apparatus to affix themselves to fish, which can eventually kill the fish. DNR photo

 

Kiss My Lamprey


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[LPS]

Have seen a few and man are they ugly..